[Objective

]

Pyrolysis represents a mainstream technology for the recycling of waste wind turbine blades. Nevertheless

it is plagued by several shortcomings

including high energy consumption

severe secondary pollution

and inferior quality of recovered fibers

which have restricted its large-scale engineering application. To tackle the aforementioned issues

a novel technology for recycling waste wind turbine blades via pyrolysis using coal-fired flue gas was investigated in this study. [Methods

]

Under simulated coal-fired flue gas conditions

the influences of flue gas temperature

pyrolysis duration

flue gas composition

and heating mode on the quality of rec

overed fibers were examined

and the corresponding pyrolysis mechanism was analyzed. Meanwhile

a pilot-scale test rig was established to validate the developed recycling technology under real flue gas conditions

and an engineering application scheme was formulated. [Results

]

The results indicate that direct heating of wind turbine blades with coal-fired flue gas can induce sequential carbonization and subsequent oxidation of the resin matrix in the blades

yielding relatively pure glass fibers and thus realizing the recycling of waste wind turbine blades. Under simulated flue gas conditions

the optimal pyrolysis process parameters for the blades are determined as follows: a flue gas temperature of 500-530 ℃ and a pyrolysis time of 4-5 h. SO

2

in the flue gas exerts no significant effect on the quality of recovered fibers. The purity of the recovered glass fibers is higher than 99%

and the reduction in tensile strength is less than 10% compared with virgin fibers. Flue gases at different temperatures are separately extracted from the inlet flue of the economizer and the outlet flue of the air preheater in the power plant boiler by a fan

mixed uniformly

and subjected to high-temperature dust removal(with the flue gas temperature controlled at 400-500 ℃) before entering a specially designed pyrolysis furnace for direct contact with waste blades to accomplish pyrolysis. Glass fibers can be recovered from the pyrolyzed blades

while the pyrolysis tail gas is synchronously fed into the furnace of the power plant boiler to achieve sufficient combustion of tar and volatile components in the tail gas

generating CO

2

H_2O

and a small amount of NO

x

. The treated tail gas is finally discharged after collaborative disposal by the existing environmental protection facilities of the power plant. The pyrolysis process is slightly exothermic

and the pyrolysis tail gas has a negligible impact on the pollutant emission performance of the power plant. [Conclusion

]

As an innovative recycling te

chnology

flue gas pyrolysis features cleanliness

high efficiency

low energy consumption and strong engineering feasibility

which can effectively address the disposal challenges of waste blades caused by decommissioned wind turbines.